


Strange Quarks

by Lauren (notalwaysweak)



Category: Big Bang Theory
Genre: Alcohol, Bondage, F/F, F/M, First Time, Multi, Sexual Experimentation
Language: English
Status: Completed
Published: 2011-03-08
Updated: 2011-03-08
Packaged: 2017-10-16 19:44:49
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 6,084
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/168690
Author URL: https://archiveofourown.org/users/notalwaysweak/pseuds/Lauren
Summary: <blockquote class="userstuff">
              <p>Amy and Penny take 'experimenting with lesbianism' to a whole new literal stage. The challenge was Penny/Amy/Sheldon and at least one of the following twenty-four prompt words: electrodes, texting, Skype, bestie, boy, friend, ties, sweaters, legs, quarks, tests, masturbation, toothbrushes, neural, penis, envy, partners, slut, sleepovers, rock, games, skin, books, orange. As I am ludicrously masochistic, I decided I was going to try to include them all, and did.</p><p>Warning for mild dub-con that turns out to be genuinely consensual.</p>
            </blockquote>





	Strange Quarks

**Author's Note:**

> The Big Bang Theory characters do not belong to me and I am making no profit off writing this.
> 
> I'd also like to note that the term 'down-home Aphrodite' was coined by Seanan McGuire in her [song of the same title](http://www.seananmcguire.com/songbook.php?id=26) and is, IMHO, a perfect fit for Penny.
> 
> Dedicated to the Realm 73 crew.

Bernadette’s out on a date with Howard, so girls’ night’s down to just Penny and Amy this time, which would be more comfortable if Amy didn’t keep staring at Penny’s cleavage. Granted, she’s wearing a thin-strapped orange top with a giant gold butterfly on the front, and it’s fairly low-cut, so maybe it’s not Amy _intentionally_ staring so much as it is just, you know, it’s kind of hard for her to _not_ look.

The part where Amy switches her gaze from Penny’s cleavage to Penny’s legs every time she stands up is a little more worrisome, but again, she’s wearing her red pajama shorts, because this is meant to be a sleepover, so it could just be an accident.

Truth or Dare doesn’t work so well with only two people, but it works a little better when Penny’s onto her third glass of wine. She’s persuaded Amy to at least try it, too.

(“Why would I want to drink fermented grape juice? Tap water will be fine.”

“Just drink it, Amy. Consider it an experiment.”

“I don’t think this is the sort of experiment that my field of research covers.”

“Truth or dare.”

“Hmmm… dare.”

“Drink a glass of the damn wine, okay?”

“Oh, very clever, bestie. Use the game to force me into drinking the alcohol. Fine, I’ll adhere to the rules.”)

The alcohol’s loosened Amy up a little. Well, a _lot_ , compared to how she usually is. She’s even wearing the pink Hello Schröddy t-shirt that Leonard got for Penny ages back, along with Penny’s Hello Kitty shorts, instead of her grey tracksuit. It makes her look cute, and as Penny sits back down with the fresh bottle of wine she tells her so.

Amy bites her lip and fidgets a little. “Thanks. You really mean it?”

“Yeah! It’s good to see you not all covered up with a sweater and stuff. I was starting to wonder if you even had any skin under there or if you were, you know, made of argyle. You should let Sheldon see you like that, he’d flip.”

“I hardly think so.”

Penny tops up both their glasses. “C’mon, Amy, he can’t be all remote and sciencey all the time. He’s still a boy.”

“I know. He’s a boy, he’s my friend, but he’s not my boyfriend.”

“So you’ve never had sex with him? It’s all just Skyping and the occasional dinner?”

The look Amy gives her is one of genuine shock. “Why would I engage in coitus with him?”

“To… save the batteries on your electric toothbrush?”

She can’t believe she’s having this conversation, for Godsakes. She thought her explaining sex to other girls days were behind her with her slumber party and underaged drinking days.

Although considering this is a sleepover and the expression Amy’s wearing is exactly like the one her friend Brittany got the first time she tried wine, even though that was out of a cask and this is out of a bottle (even if it’s a cheap bottle), maybe those days aren’t so far behind her after all.

Amy shakes her head. “I don’t feel that kind of attraction to Sheldon.”

“Well… why not?”

“I thought Truth or Dare meant taking turns asking questions,” Amy says pointedly. “Given that fact, maybe you should tell me _why_ I should be physically attracted to Sheldon.”

Penny has to stop to think about it for a moment, but _only_ a moment. Thing is, she’s got a habit of sizing up guys when she meets them, and although Sheldon made it pretty clear early on that he wasn’t interested in that sort of relationship, it didn’t keep her from noticing a few things.

“He has stunning eyes and a gorgeous mouth and sexy arms,” she says.

“I don’t understand. How does one quantify arms as ‘sexy’?”

“One doesn’t _quantify_. One just _looks_.”

Amy swirls the wine in her glass. “Oh.”

“ _Drink_ that. Besides, you know about this stuff. You complimented me on, um, my ‘bodacious’ secondary sexual characteristics.”

Amy downs half her glass of wine with a somewhat defiant look on her face and licks a drop of it off her lower lip. “Your cleavage is far more readily noticeable than Sheldon’s _arms_.”

Penny takes a second to process this. “Are you saying I dress like a slut?”

“That wasn’t my intended implication! I merely meant that your clothing showcases your breasts far more readily than Sheldon’s showcases his arms.”

“Oh, come on. You know how his long-sleeved t-shirts stop at the elbow? Perfect for showing off his forearms and hands.”

“I think that’s more for convenience at work than intended as any sort of overt sexual attractant. Besides, Sheldon’s made it abundantly clear that he’s not interested in coitus. It was one of the very first parameters I specified at the beginning of our friendship, and he agreed.” Amy lifts her wine glass again as if to hide behind it.

“ _You_ said you weren’t going to have sex?”

Amy nods.

“But…” The words stick in Penny’s throat, but a quick slug of wine loosens them. “But you checked Zach out, and you masturbate, and you, um…” She gestures at her bedroom door. “At our first slumber party, you _made out_ with me.”

Amy nods again, looking a little hopeless. “What can I say, Penny? Even the hardest rock will succumb to the pressure of water over time. I’ve tried not to give in to my primal instincts, but it’s incredibly difficult to do so when surrounded by the constant stimuli that not only exist in the world, but are forced into one’s brain by the content of movies and advertising and books and so on.”

“Are you saying you got brainwashed into being horny by the _media_?”

“I’m not ruling it out.”

“So you _do_ want to have sex with Sheldon?”

“I’m not ruling that out either--”

“Aha!”

“--but it’s unlikely. While I do have some degree of attraction to the male form, it’s not my first preference.”

The sudden silence between them is almost palpable. Penny hates it when party games turn out this way, with some unexpected revelation that leaves everyone stunned. But then again, it’s not all _that_ unexpected, really, she has to admit.

Amy finishes her wine and reaches for the bottle. Penny catches her wrist. “Are you sure you should be drinking any more of that? You’re starting to worry me.”

“I think I know my limits.” The _s_ in _limits_ comes out slurred.

“I’m not so sure that you do.”

Amy’s hand twists in Penny’s grasp and suddenly her fingers are around Penny’s wrist instead of the other way around, and she _pulls_ , and Penny’s just glad they both set their glasses down because otherwise they would have gone flying.

“I’m always willing to test them,” Amy breathes, lips an inch from Penny’s as Penny sprawls across her. “Are you?”

And because they’re drunk, or because she’s lonely, or because she feels sorry for Amy with all that sexual tension building up within her while Sheldon moves through his life completely oblivious, Penny’s the one who closes the distance between them.

Amy tastes like wine and chapstick and the little cheesy biscuits they’d been munching on earlier. Her mouth opens willingly under Penny’s and her tongue strokes along Penny’s and both of them gasp a little. Neither of them make a move to do anything but kiss for a good few minutes, but then Penny feels Amy’s hand, slim and warm, slipping up under her top, and she starts giggling.

“What? Does that tickle?”

“No. I was just thinking… you know what I said about how seeing you dressed like that would make Sheldon flip? Forget that; seeing _this_ would make him flip.”

Amy ponders this for a second, her fingers idly resting just below Penny’s breast. “We should find out.”

“What?”

“We should go over there and make out in front of him and see how he reacts,” Amy succinctly summarizes her experiment idea.

Penny bites her lip. She hadn’t exactly factored an audience into her plans for the evening, but then, she hadn’t exactly factored making out with Amy into her plans either, and... hell, she hadn’t exactly _made_ plans for the evening beyond buying the wine and biscuits and renting _Never Been Kissed_.

“I don’t think so.”

The disappointment is plain on Amy’s face. “But it would be an interesting experiment! I could hook him up to the EEG and everything!”

“You still have that with you?”

“Miraculous discoveries in science don’t adhere to laboratory opening hours, bestie.”

“Well, anyway, I meant no, we shouldn’t go over there. What if Leonard’s there? We should get Sheldon to come over here instead.”

Amy grins. “I like your methodology!”

Penny’s pretty sure that means _good idea_. “Let’s do it. You call him.”

Amy’s already pulling her hand back out from under Penny’s tank top and reaching for her bag. Penny slides back off her, dropping one last quick kiss on her cheek, and moves to make her own preparations.

* * *

Sheldon wasn’t sure what to expect when Amy texted him to summon him – ALONE, she’d stressed in all caps – to Penny’s apartment to take part in some sort of experiment. It certainly wasn’t what happens, which is that as soon as he finishes knocking and saying, “Penny and Amy,” three times, the door opens and his wrist gets grabbed and the next thing he knows he’s sitting in the chair he claimed as his while Penny completes a neat clove-hitch around his wrist with what he recognizes as the cord from her bathrobe.

“What on earth…”

The cord’s threaded under the chair, presumably wrapped around the base, and she’s knotting the other end around his other wrist, her face intent and flushed with alcohol. He can smell wine on her breath. She’s unnervingly close to him, as if the fact that she’s tying him to a chair weren’t unnerving enough on its own.

“Penny, what…”

He feels the squish of electrode gel being rubbed onto his scalp and tilts his head back to see Amy with a handful of wires, sticking them on one by one, with a similarly absorbed and similarly _drunk_ facial expression. He’s used to the electrodes from various neural tests over the years; what he’s not used to is having them stuck on by someone who’s squinting because she’s seeing double.

Penny’s done with the bathrobe cord and for good measure binds his wrists together in his lap with one of his own ties that he remembers went missing on laundry night three weeks ago. Evidently it got mixed in with Penny’s laundry and she failed to return it to him. However, her carelessness in neglecting to do so isn’t his primary concern at this moment in time.

“Penny! Amy! What are you _doing_?”

Amy moves to stand in front of him and he gets his second big shock of the night: she’s wearing Penny’s clothes. The tight pink shirt and white shorts reveal far more of her than he’s used to seeing. Naturally Penny’s wearing even less, but he’s become accustomed to that.

“We’re conducting an experiment,” Amy announces.

“You said as much on the phone, but…” Sheldon looks from one of them to the other and then down at the bindings keeping him in the chair. He supposes he could pull free if he really wanted to but, despite being utterly perplexed, he does want to know what they’re up to. “I don’t understand.”

“Amy ‘n’ me ‘re research partners,” Penny says, slipping her arm around his not-girlfriend’s waist and pulling her close. “We’re studying… what’re we studying, again?”

“The effects of watching lesbian activities on the male brain, with a series of tests designed to increase the intensity of the stimuli and observe the correlating brainwave activity.” Amy manages this with surprisingly little slurring. “Although I think it would work better with a sphygmomanometer attached to the relevant area.” She doesn’t make it through “sphygmomanometer” without a few too many _mo_ s in the middle.

Sheldon didn’t know one’s jaw could literally drop, but his does. Lesbianism? Stimuli? _Sphygmomanometer_? “Amy, you are not attaching a blood pressure cuff to my penis! You’re not attaching _anything_ to my penis!” He pulls at the cord but Penny ties a mean knot and it won’t budge. “Let me up!”

“No,” the two of them chorus.

“This is absurd!”

“No, it’s _science_ ,” Penny says.

“It’s not even remotely scientific!”

“It’s got to be science, look at all the wires.”

Clearly he isn’t going to get anywhere appealing to her with logic, so he tries a different tactic. “I’ll call Leonard.”

Penny snorts. “Oh yeah, so he’ll come over here and see you like this? Get real.”

Amy cranes her neck to look at the EEG readout. “I believe that’s established enough of a baseline with your usual banter,” she says, and before Sheldon can protest that this is _far_ from their usual banter, the two of them are kissing.

 _Oh._

Amy’s got her hands in Penny’s messy blonde hair, running her fingers through the strands, letting them fall in a curtain that only partially obscures their faces. Penny’s hands are around Amy’s waist, linked behind her back. Amy has to tilt her face up a little to Penny’s; Sheldon’s never really noticed that she was that little bit shorter than Penny, and he’d definitely never noticed the way her neck makes a taut straight line when she looks up like that. In fact, Amy seems to be made up of a lot of lines: her straight hair and slim build and even her fingers in Penny’s hair, while Penny’s all curves and curls.

He’s pretty sure that this sort of experiment is the kind of thing that would be better conducted on someone like Wolowitz, but he’s also pretty sure that this isn’t something they’d test out on just anyone. No. They’re targeting him intentionally.

“Your participant sample is too small to draw conclusive results,” he tries.

Amy’s lips part and he can just see Penny licking at her lower lip before their mouths are joined too tightly together to see just what’s going on, even though he catches himself leaning forwards to try and get a better view. Penny’s hands move down to cup Amy’s backside and Amy makes a surprised little noise and Sheldon sees the corner of Penny’s mouth curve up in a secret smile.

Wolowitz, he decides, would be green with envy if he could see this. He doesn’t mention this aloud, though; Penny’s punches are as strong as her knots.

He doesn’t need to look sideways at the EEG readout to know that at this point it’s doubtless quite active. He can feel his own elevated pulse, the heat in his cheeks as he looks at the two of them, bodies still clothed but pressed so close together it’s like the thin layers of fabric aren’t even there. Most of all, he can feel his undeniable arousal, and is glad that his hands are in his lap so he can keep that, at least, secret.

Amy breaks the kiss off after what seems like a very long time, turning to eye him speculatively before letting go of Penny and stepping backwards out of their embrace, moving so she can see the EEG readout. She nods, apparently unsurprised by what it’s telling her.

“It’s working, right?” Penny asks.

“Our hypothesis is being supported.” The smile Amy flashes to Penny is downright wicked. “But I think we need more data to be sure.”

“More da-- oh!” Penny yelps as Amy pulls her close again but keeps going backwards until the two of them are sprawled inelegantly on the couch in a tangle of limbs. Sheldon swallows hard and presses his bound hands down against himself in an attempt to relieve or at least deflect some of the tight-wound clockspring pressure between his legs. It’s an empty gesture; there’s only one way that that pressure can be relieved and he knows it.

“Experiment over. Let me go,” he says.

He’s not even sure they _hear_ him, but they sure as hell don’t get up and let him go.

Amy’s hands slide up under Penny’s top, pushing the fabric up out of the way, and Penny braces herself against the back of the couch for a moment, kneeling between Amy’s legs so she can help pull the top up and off. She glances over at Sheldon and tosses the orange handful at him and it lands on his shoulder; the smell of her cheap laundry detergent wafts up from it, citrusy and clean.

Then she stops paying any attention to him because Amy sits up a little further and closes her mouth over one of Penny’s nipples, and Penny lets out a familiar strangled moan.

Sheldon scrunches his eyes closed and tries to think about anything but this. Atoms. Neutrinos. Quarks. Up quarks; down, top, bottom quarks. Strange quarks. Charm quarks. Oh dear. There definitely aren’t any weak interactions involved here; they’re all quite strong. His eyes open again and Penny’s still braced against the back of the couch but this time it’s clearly because of what Amy’s doing to her. He can imagine how hot Penny’s skin must feel under Amy’s mouth, how intense the pleasure Penny is clearly experiencing must be. He realizes he’s rubbing himself through his pants and jerks his hands away; seconds later they’re back where they were.

The two of them shift position a little as Penny unceremoniously yanks Amy’s t-shirt up over her head. She tosses it at Sheldon but misses; her coordination’s not what it was, her focus not as good. She lowers herself to press her body against Amy’s and the gasp they both let out as their bare skin meets drowns out Sheldon’s own shocked sound.

Normally he tries to ignore his arousal or takes care of it as quickly and clinically as possible, seeing it as a distraction from the pursuit of his work, his Nobel Prize dreams. But he’s at least twenty feet from his whiteboard, and moreover he’s not going to get untied until they’re ready for him to be untied, and so he gives in and just watches them, although lord knows what Amy’s going to be able to make of the EEG readings after the fact, because although she’s clearly escalated the intensity of the stimuli as intended, she hasn’t stopped to mark the transition from one stage to another and Sheldon is quite certain that she’s not timing this.

Penny seems to be taking charge, judging from the quality of the noises that Amy’s making and the way Penny’s moving against her, administering kisses to her neck and chest before removing Amy’s glasses and setting them aside out of harm’s way. She likes to be the dominant partner, Sheldon recalls, and free-associates: dominant, top. Top quarks. He’s never going to be able to think about top and bottom quarks in the same way ever again, much less charm quarks. Although considering the way that the image of the two women entwined in front of him is burning itself into his cerebral cortex he’s not sure he’ll ever be able to think about _anything_ in the same way ever again.

“Is he still watching?” Amy asks, blinking up at Penny.

Penny glances sideways at Sheldon, eyes locking on his and then raking down his body to where his hands are cupped together. “Oh yeah, he’s watching all right.” Her voice holds laughter; even he can recognize that.

“Good. You know how stubborn he can be. I was wondering if he’d closed his eyes.”

Penny just shakes her head and then, her gaze returning to Sheldon’s face, slips one hand down between their bodies, between Amy’s legs, and Amy’s the one who closes her eyes, letting out a shuddering gasp and squeezing her thighs together. Penny still seems to have some room to move her fingers, though, as the red flush on Amy’s cheeks intensifies and spreads down her neck.

“Sure, he’s stubborn, but some things are irresistible.” Her gaze challenges him to retort, but he doesn’t have a comeback to that. About the only thing he can do at the moment is squeeze himself through his pants so he doesn’t come in them.

Speaking of which, that’s exactly what Penny’s apparently intent upon making Amy do. Sheldon watches the play of the muscles along her forearm, the tension in her tendons, and he’s sure that he’s read articles about the difference in difficulty in achieving orgasm between men and women but Penny seems to be having no trouble in pushing Amy towards that point with whatever she’s doing with her fingers.

He realizes he’s leaning forwards again to try and see better and sits bolt upright and Penny smirks, leaning down to whisper something in Amy’s ear. Amy blinks, then nods and moves slowly, as if she’s drugged (alcohol is technically a drug, even if oxytocin and dopamine aren’t), until she’s sitting up, legs spread, leaning back with Penny kneeling beside her, and _now_ Sheldon can see the flex and press of Penny’s fingers, first against the thin cotton of Amy’s shorts, and then the shapes they make under the material as Penny slips her hand inside to touch Amy directly.

This time Sheldon knows they hear the noise he makes, an animalistic choked moan, because Penny smirks again and Amy, although she is quite distracted by Penny’s actions, lets out a breathy little giggle quite unlike anything he’s ever heard from her before. But then again, none of their previous interactions, not texting nor Skyping or going out to dinner together, ever involved such a scenario.

He’s wondering if an EEG machine can explode, given enough neural activity. Out of the corner of his eye he can see the readout racing. He can’t tear his gaze from the women long enough to properly examine and evaluate what it’s saying, though.

Amy’s hips are moving, swaying up against Penny’s hand. She has her eyes closed and is breathing rapidly. Her own brain waves would be quite a sight at the moment, but Sheldon has the feeling that interrupting them to point this out would be quite unwelcome.

Penny lowers her head to take one of Amy’s nipples into her mouth, golden hair falling down around her face like a veil, but even without her challenging stare locked on him Sheldon no longer has any inclination to close his eyes or look away. Unconsciously his hand is moving against himself, rubbing in a rhythm that mimics the movements of Penny’s fingers. If he’s making any noise it’s drowned out by Amy, though, who, as she writhes and moans under Penny’s touches, bears very little resemblance to the buttoned-up scientist he first met.

Amazing what a little ( _a lot_ , he mentally corrects, counting the bottles on the table, estimating the units of alcohol in each, and then dividing by two to come up with a fairly large number) wine will do.

“Oh God, Penny,” Amy says, her voice shaky.

“ _Yes_ ,” Penny returns as she lifts her head, her fingers working mercilessly on and in Amy, whose shorts have slipped down far enough that Sheldon can just see the way Penny’s got two fingers buried inside her and is rubbing her clitoris with her thumb. “Come on, come on, come…”

Amy voices an inarticulate cry and her lower body surges up off the couch. Sheldon squeezes down hard because walking back over to 4A with a wet spot on the front of his pants is not something he wants to explain to Leonard.

Penny’s staring over at him, hair tumbling over her face, looking feral, predatory, and Amazonian, and it doesn’t matter one whit that the Greek Amazons weren’t blonde, because nor is Penny as chaste as the Greek Penelope, and it’s quite clear from Amy’s gasping and wriggling that Amy likes her the way she is.

Sheldon likes her the way she is too. She isn’t virtuous Penelope; she’s more of a down-home Aphrodite, and it’s disturbingly, undeniably attractive.

Penny withdraws her hand from Amy’s shorts and kisses her softly. Amy kisses her back and then murmurs a question to her that Sheldon doesn’t catch save for the uptilted inflection at the end of the sentence. Penny shakes her head and looks back over at Sheldon, and Amy laughs, as though she’s unsurprised by this response to whatever she asked, even though Penny didn’t actually _say_ anything.

“Are you two quite finished with your experimenting yet?” Sheldon asks, willing his voice to stay steady.

“Not quite.” Penny gets up and moves to stand in front of him, looking down at him, particularly at his hands, which he shakes at her.

“I think the circulation’s getting cut off.”

“Oh, bullsquirt. I didn’t tie it that tightly.”

She’s right. He’s only trying to bluff his way out of his bonds. But when she drops to one knee in front of him and starts pulling his shoes and socks off, he wonders why he bothered. This isn’t going to stop until both of them are finished with whatever they’re planning to do next, unless he insists upon it, and then Penny’s running her hands slowly up his calves and then his thighs and suddenly the only thing that he wants to insist on is that she not stop at all.

Amy seems unbothered and unsurprised by the way her bestie is touching her not-boyfriend. She’s pulling the pink t-shirt back on, her nipples dark peaks under the thin fabric, and examining the EEG readout. Sheldon can see a certain awkwardness in the way that she moves that isn’t due to the alcohol; it’s more of a wobbly-leggedness, and he knows why _that_ is.

Penny’s tank top is still on his shoulder. Amy leaves it there rather than offering it to Penny. When Penny stands up and hooks her thumbs into the waistband of her red shorts, sliding them down her legs and off, the full implication of what she’s planning to do next hits Sheldon and he inhales sharply.

“He’s definitely aroused,” Amy says, studying the EEG. “Brainwaves, physiological signs…”

“…hard-on,” Penny finishes dryly, lifting Sheldon’s hands out of the way and yanking at his belt. “Trust me, Amy. This field of study I _do_ know.” She slips the tongue of the belt out of the buckle and flicks the button beneath open with her thumb. She doesn’t seem nearly as drunk as she did before.

“Penny…”

“Yes, sweetie?” She stops, moving her hands away from him, maybe in response to something in his tone of voice.

Sheldon closes his eyes briefly, thinks about up and down and top and bottom and how they can transform so quickly, so easily. He’s not even sure if he’s thinking about quarks any more. Then he opens his eyes again and says quietly, “Don’t stop.”

He can read the expression on her face this time too: it’s relief.

She makes short work of getting his pants and underwear off and even puts them relatively neatly on her coffee table instead of throwing them anywhere. Sheldon looks at Amy to see how she’s reacting to this, but she’s just curled up at the end of the couch, watching them. Her glasses are still on the coffee table, but that doesn’t seem to bother her. She looks sleepy, sated.

Then Penny’s hand closes around him and Sheldon forgets everything but that raw pure physical contact. She’s back on one knee in front of him, looking up at him, and he feels a little ridiculous sitting here with his double t-shirts – oh, and his tie, mustn’t forget his tie, even if knotted around his wrists is not where he traditionally wears it – while she’s completely bare.

“Your hands are in the way,” she complains.

“ _You_ put them there.”

Penny rolls her eyes, an oddly prosaic gesture in an extraordinary situation, and with a quick pull on one end of the tie unravels the whole thing, freeing his hands – well, mostly. He can draw them back out of her way, but he can’t lift them more than a few inches from the arms of the chair. Not that that seems to matter, considering Penny is well and truly in control here, whether the person she’s ravishing is tied to anything or not.

She turns away for a moment, fishes her bag out from underneath the coffee table, and digs through it, making an _aha_ noise when she finds what she’s looking for.

The sensation of doctor’s-glove latex against him is familiar, but this is quite different; tight and slick and she rolls it on a little way with her fingers and then gives him a mischievous grin and plunges her mouth down on him to roll it on the rest of the way with her lips, and Sheldon sucks his lower lip in between his teeth and bites it because if Leonard hears him getting too loud he’ll come over here to investigate and Sheldon’s not sure if anyone locked the door.

Penny stays down there for another few long tingling sucks, like she’s making sure she prepared him right, and then stands back up, moving to kneel astride him on the chair.

“Penny, are you sure you’re adequately lubricated?” Amy pipes up.

“Trust me, I’m good to go.” But she stays balanced across Sheldon’s lap for a moment. He can feel her heat against him, so close. She presses her forehead to his and whispers, “Is this still okay?”

“Do I have a choice?”

She draws back, looking wounded. “Of course you do. God, Sheldon, I’m not about to – to _force_ myself on you.”

“Can you untie my hands?”

She lowers her hands to the cord, deftly flicking each knot open, and she’s about to back away to let him up when Sheldon catches her around the waist.

“I’m choosing this,” he murmurs, and pulls her down onto him.

Indescribable. Warmth and tightness and _God_ he got a preview of this when she put the condom on him but the reality’s so much more and she’s rocking astride him, her knees tight in against his thighs, cramped up in the small space the chair affords them, but relocating at this point is not an option, not even remotely, because that would mean stopping and he doesn’t want this to stop, not even briefly.

Her mouth finds his and he can taste the sharp tang of wine on her tongue as it slips between his lips, because protesting against exchanges of saliva seems utterly redundant at this point in time.

Penny makes a sudden surprised noise into his mouth and Sheldon opens his eyes to see that Amy’s joined them after all, her hands sneaking in between the two of them, one cupping one of Penny’s breasts, the other resting flat on Penny’s thigh, tantalizingly close to where they are joined, which isn’t a method for testing neurobiological reactions in any publication that Sheldon’s ever read but he knows by now that that’s not what this is about. Amy lifts Penny’s breast a little, thumb circling over the hard little peak of her nipple, and Sheldon dips his head to follow her thumb with his tongue.

“Sheldon… Amy…” Penny barely squeaks their names out.

Amy’s other hand moves inward on Penny’s thigh. Sheldon can feel her fingertip nudge against him before it moves again and Penny doesn’t seem nearly as concerned about being noisy as Sheldon was. Sheldon lifts his head to catch her mouth under his again; she can make all the little moans and whimpers she wants now and he can muffle them.

She’s making a _lot_ of them.

All of a sudden he can feel her tighten around him and she’d be screaming if it weren’t for his mouth pressed against hers. She rides down hard against him and that’s all it takes to tip the balance and he’s gone, hands tightening on her waist, holding her close, her name escaping his lips as a drawn-out, “ _Pen-nyyyy_.”

Penny’s head drops to his shoulder as she tries to get her breath back. Amy withdraws her hand from between them and licks her fingers. Sheldon would raise an eyebrow at her but he feels like he’s turned into jelly, like all the energy in his body ran out just then. He just holds Penny on his lap and closes his eyes and listens to the way her breathing slows from erratic-fast to satisfied-slow.

After a few minutes Penny stirs and lifts up off him, rubbing her calf and glaring at it like she’s just daring it to cramp up. Sheldon stands up, his body protesting this change in position, picks up his pants and underwear, and retreats to the bathroom to clean up.

* * *

Penny waits until the bathroom door closes and there _isn’t_ an outbreak of horrified sobbing from beyond it before she gets back into her clothes. Amy’s looking at the EEG again; Penny pushes her hair aside and kisses the back of her neck and Amy leans back against her and sighs happily.

“I think that experiment went very well, Dr Fowler.”

“Agreed, bestie.” Amy sounds sleepy. “I may have to keep calling you ‘bestie’, though; I’m not sure society has a word for ‘experimental sexual partner’.”

“Pretty sure that’s still just ‘slut’,” Penny says with a not so happy sigh of her own.

Amy turns in her arms and slips her own arms around Penny’s waist. She’s still not wearing her glasses; her face seems somehow softened without them. “We’ll find a different word,” she says quietly.

Penny takes a step sideways and pulls her down onto the couch, gently this time, and just holds her close.

* * *

This is how Sheldon finds them when he returns from the bathroom, as cleaned up as he can reasonably explain. He still has electrode gel in his hair, but that takes a good long shower to remove, and coming home from Penny’s freshly showered would lead to extensive questioning from Leonard.

This is how he finds them, wrapped in each other’s arms, sitting on the couch, Amy already half-asleep, head tucked against Penny’s shoulder. He sits down to put his shoes and socks back on. Penny’s eyes meet his and she gives him an uncertain but sweet smile.

“I propose that the final stage of this experiment be a good night’s sleep for all participants,” he says once he’s fully dressed.

“Mmmm,” Amy says drowsily. “Seconded.”

“Motion carried,” says Penny, disentangling herself from Amy and then picking her up. “Night, Sheldon.”

“One moment.” Sheldon stops her before she can carry Amy to bed. He kisses Amy on the cheek and then Penny on the lips. “Sleep well.”

“Sweet dreams,” Amy murmurs from her half-sleep.

“No doubt.”

* * *

Penny settles Amy onto the bed and pulls the covers up over her, then crawls in beside her. She’s pretty sure that there won’t be any night terrors for the other woman tonight.

Where they’ll go from here she doesn’t know, but she’s too tired and sated to worry about it overmuch, and just lets her head sink into the pillow and her thoughts into the realm of dreams, where when Amy bites her it’s a very specific sort of bite and not one that she minds at all.

* * *

Leonard’s still up watching television when Sheldon walks into the apartment, but he looks up from _The IT Crowd_ long enough to ask, “Everything okay? I thought I heard you yell.”

“Electrode gel is sticky and it hurts when you pull it off,” Sheldon says, which isn’t a lie.

“Oh. Ouch,” Leonard says, and returns his attention to Roy, Moss, and Jen.

Sheldon goes down the hallway to his room. He wants to go and shower and get the gel out of his hair (it really _is_ annoying), but he’s worried that Leonard will think something is up if he showers now, since it’s not his usual shower time. In the end he settles for combing his hair as hard as he can stand to and then changing into his pajamas and settling into bed. He can stick to his usual routine on the shower front at least considering everything else tonight has deviated so far from it.

Besides, he finds he doesn’t mind the notion of having the combined scent of the two women lingering on him for just a little longer.


End file.
